Comment by jorams
14 hours ago
It's a bit buried, but it does:
> In contrast to conventional radial flux motors, the electromagnetic flux in an axial flux motor runs parallel to the axis of rotation. The key components are arranged in a disc‑shaped layout: two rotors sandwich the stator from the left and right. This design enables an especially compact motor architecture, high power and torque density, and new freedoms in drivetrain packaging. In the new Mercedes‑AMG GT 4‑Door Coupe, the motor at the front axle is just under nine centimetres wide; the two motors at the rear axle each measure around eight centimetres in width. The three axial flux motors are integrated per axle into so‑called High Performance Electric Drive Units (HP.EDU), where they are combined with a compact input planetary gearbox in a single housing.
> The three axial flux motors are integrated per axle
I wonder why they need tree motors per axle.
It's poorly worded. There aren't three motors per axle, there are three motors total: one on the front axle and two on the rear axle.
The translation's a little woolly.
For the AMG GT4 there will be 3 motors: two at the rear, and one at the front.
My interpretation (and my German's pretty lousy) is that each motor is combined with a gear system in a single package, and they're calling the overall package (motor plus gears) a High Performance Electric Drive Unit (HP.EDU).
The two rear motors will probably be independent, so no need for a mechanical rear diff (it'll be electronically controlled).
There's no mention of a front diff, so it's unknown whether that's built into the front HP.EDU or is a separate mechanical diff).
In terms of traction control, does this translate to something between "4WD" and "AWD"? Or is it orthogonal?
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To build on what others have said. Multiple motors per axle allow you to get rid of the diff, and you get torque vectoring basically for free.
Then there's braking. More driven wheels means more braking energy that can be recouped via regen. In traditionally rwd cars you lose out here because braking energy tends to be directed forward.
Also there's packaging. One large motor might impinge on the cabin.
Also you get benefits wrt mass production.
A smaller motor is easier to handle. Potentially could avoid the need for high voltage cables. Which eases repair.
I got the impression that there were three motors altogether and they were integrated with the axles.